New Accelerating Test Methods for Board Level Solder Joints and Thermal Caused Failure Mechanisms in High Temperature Electronics

Board-level reliability of conventional Sn-37Pb and Pb-free Sn-3.0Ag-0.5Cu solder joints was evaluated using thermal shock testing. In the microstructural investigation of the solder joints, the formation of Cu6Sn5 intermetallic compound (IMC) layer was observed between both solders and Cu lead frame, but any crack or newly introduced defect cannot be found even after 2000 cycles of thermal shocks. Shear test of the multi layer ceramic capacitor (MLCC) joints were also conducted to investigate the effect of microstructural variations on the bonding strength of the solder joints. Shear forces of the both solder joints decreased with increasing thermal shock cycles. The reason to the decrease in shear force was discussed with fracture surfaces of the shear tested solder joints.

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Application of Small Punch Test to Evaluate Tensile Properties of SA213T22 Grade Boiler Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.830-831.191 ◽

2015 ◽

Vol 830-831 ◽

pp. 191-194

Author(s):

M. Venkateswara Rao

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Tensile Properties ◽

Test Methods ◽

Uniaxial Tensile ◽

Test Results ◽

Small Punch Test ◽

Small Punch ◽

Punch Test ◽

Aging Phenomena

Conventional tensile test methods are used for service exposed high temperature boiler tubes to evaluate the deterioration in mechanical properties such as tensile strength, yield strength and percentage elongation. The mechanical properties are required to be evaluated periodically as the boiler components undergo material degradation due to aging phenomena. The aging phenomena occurs due to continuous exposure of tubes to high temperature & pressure steam prevailing inside the tubes and high temperature exposure to corrosive combustible gases from the external surfaces within the boiler.A recent developed new technique called small punch testing has been used to evaluate the tensile properties of SA 213T22 grade steel predominantly exists in super-heater and re-heater sections of boiler. The small punch tests have been carried out on the miniature disk shaped specimens of diameter of 8.0 mm and 0.5 mm thickness extracted from both the new and service exposed tubes. Conventional uniaxial tensile tests on standard specimens from the same tube material have also been performed for comparison. The service exposed tubes showed considerable loss in mechanical properties in both the conventional and small punch test results. Correlations of tensile properties have been obtained based on the comparative analysis of both small punch and uniaxial tensile test results. Further, the study showed that an appropriate empirical relation could be generated for new and service exposed materials between both the techniques. Conventional test methods require large quantity of material removal for test samples from in-service components whereas small punch test method needs only a miniature sample extraction. This small punch test technique could also be extended to evaluate the thicker section boiler components such as pipelines and headers in the boiler as a part of remaining life assessment study. Also this technique could be a useful tool to any metallic component where large quantity of sample removal may be difficult or may not be feasible.

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Effect of high temperature thermal aging on microstructural evolution of Sn3Ag0.5Cu/Cu solder joints

2013 14th International Conference on Electronic Packaging Technology ◽

10.1109/icept.2013.6756579 ◽

2013 ◽

Author(s):

Hailong Li ◽

Mingliang Fu ◽

Mei Zhu ◽

Rong An ◽

Chunqing Wang ◽

...

Keyword(s):

High Temperature ◽

Microstructural Evolution ◽

Thermal Aging ◽

Solder Joints

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